Method of making asphalt



Dec. 20, 1932. p KElTl-LJR 1,891,890

METHOD OF MAKING ASPHALT Filed July 10, 1928 (Hum MM:

Patented n... 20, 1932' UNITED STATES PATENT or fice;-

PERCY c. .xnrrn, 3a., or BEBNABDSVILLE, NEW mnsnir, assienoa, BY men;as-

sremrmrrs, TO GASOLINE PRODUCTS COMPANY, INC OF A CORPORATION OFDELAWARE NEWARK, NEW JERSEY,

mnon OF MAKING ASPHALT Application filed July 10, 1928. Serial No.291,601.

This invention relates to the roduction of commercial asphalt fromcradkingcoil tar and will be understood from the following descriptionread in conjunction with the drawing which is an elevation principallyin section of apparatus in which my method'may be carried into effect.

Petroleum oil to be cracked is introduced through the 'ipe 1 controlledby valve 2 to the tubular eater 3. The tubular heater consists of anumber of sections of tubing joined end to end by cross-over connectionsto form a continuous circuit. It is surrounded by the refractory setting4 and may be heated through port 5 by means of the burner 6. The heatingis 'so conducted that the material is heated to a relatively hightemperature, usually above 800 F., and is then discharged through pipe 7into thedigestion chamber 8. This consists of a drum,preferably-surrounded by insulating material 9, in which the crackedpetroleum oil is retained for a further period durin which crackingreactions proceed, principa ly as a result of the contained heat. Theprecise form of tubular heater and digestion drum are unimportant; anyalternative type may be employed in place of those specificallyillustrated. The tubular heater is known in the trade as a cracking coiland will be hereinafter referred to as such. Ordinarily the coil anddrum operate under pressure considerably in excess of atmospheric,frequentl as high as several hundred pounds gauge, w ich may be reducedat the outlet 10 by a reduction valve such as 11. The cracked materialwhich is continuously abstracted from the digestion drum is introducedat reduced pressure, say 15 pounds gauge or less, into the low pressuredrum 12 through the pipe 11a. The cracked material is preferablydischarged into this drum through a perforated pipe such as 13.Separation takes place in the drum 12, tarry material collecting in thelower part thereof while vapors which are substantially tar free passoff overhead through the pipe 14. When operating under extremely highpressures in the coil and drum, or during vapor phase operation, it isfrequently advisable to introduce petroleum oil with the crackedgnaterial, which may be done by means of the oil inlet pipe 15controlled by valve 16 and discharging into pipe 11a. While any oilintroduced in this manner will absorb the super-heat of the crackedmaterial and control the consistency of the tar produced, it isdesirable to introduce through the pipe 15 an oil containing tar-formingconstituents which will add to the tar produced by cracking and theadditional benefit will be simultaneously derived in separating thetar-forming constituents from the oil so introduced. The vapor passingoii' through 14 enters the rectifying column 17. This consists of anysuitable type of rectifying equipment; that shown is provided with theconventional partitions which carry over-flow pipes and vapordistributors of any suitable character, not shown. Condensation isproduced by cooling coils in the upper part of the tower such as 18 and19. The C011 19 may conveniently be supplied with oil for thecrackingcoil which is thereby pre-heated prior to cracking. The totalamount of cooling obtained by the use of coils 18 and 19 is preferablyso controlled that the final vapor passing ofi through the pipe 20consists essentially of gasoline which may then be condensed and workedup for the market in any approved manner. Aliquid bottoms collects inthe base of the tower 17 and is preferably withdrawn continuouslythrough the pipe 21 and pumped by means of the pump 22 through the pipe23 controlled b valve 24 back into the cracking coil, there yrecirculating the 35 said bottoms and adding to the total quantit ofgasoline produced. The drum .12 is re erably surrounded by insulation12a an the tar collectingin this drum is withdrawn continuously oreriodically by means of the pipe 90 25 controlled by valve 26 andthereby d18- charged into the intermediate portion of the stripping drum27. The pi e 25 is preferably surrounded by insulation 26a so that thetar may be introduced substantially without loss of heat into theintermediate portion of the drum 27. This drum carries horizontalpartitions 28 equipped with the customary vapor distributors andover-flow pipes, not shown, below the point of introductor 33. The drum27 preferably carries.

foraminous plates 34 above the point of introduction of the tar, whichmay in turn carry tile or other bafiling means, not shown, to knock downentrainment from the ascending ..vapor. Vapors may be conducted from thedrum 27 through the vapor pipe 36 which discharges into the condenser37. This condenser consists of an elongated drum provided with waterinlet 38 at the lower end and water outlet 39 at the upper end. A numberof tubes 42 are arranged within the drum between the two header plates40 and 41 so that the water circulates within the tubes 42.

Any oil va or discharged b the pipe 36 circulates in t e space externato the tubes and is thereby condensed. The condensate is continuouslywithdrawn through the pipe 44 discharging into the accumulator 45 .fromwhich it may be continuously or periodically withdrawn by means of thepipe 46 connected to the pump 47 and thereby diverted through the pipe48 to any suitable accumulator. By means of the pi e 49 connected to theaccumulator 45 and t e vacuum pump 50 the condenser 37 and drum 27 aremaintained under vacuum. The vacuum pump 50 may be of any suitable t ealthough that illustrated diagrammatical y is barometric. .The operationof the cracking coil will be obvious to those familiar with the art. In0 erating theequi ment for the reduction 0 the tar produc by thecracking equipment a vacuum is applied through the condenser 37 to thetar discharged into the drum 27. I preferably employ a. vacuumcorresponding to an absolute pressure of less than 100 mm. of mercury.This automatically results in a considerable reduction of the tardelivered by the pipe 25. In consequence of the retained heat of the tarthis is distinctly assisted by the fact that the tar when brought fromthe cracking system may be at a temperature of 700 or 800 F. Thereducing effect of the vacuum ap lied to the heated tar is furtheraugmente by the strip in effect of the steam introduced through t eistributor 33 and the additional heat applied by means of the coil 30.The coil 30 is preferably supplied with super-heated steam for thispurpose. The effect of these agencies is so controlled as to roduce a liuid residuum in the bottom 0 the drum 2 corresponding to a commercialasphalt. By means of the overflow pipe 51 the level of this material inthe bottom of the drum 27 is maintained above the coil 30, any excessbeing continuously diverted through the overflow pipe 51 controlled byvalve 52 and transferred by means of the pump 53 to'any suitableaccumulator. The

ade of material produced may conveniently include all of those productswhich are generically covered by the term asphalt and which range fromthe liquid or semi-liquid products known as bindersdown to theproductswhich are solid at normal temperatures and which constituteasphalts of relatively high melting oint and low penetration.

The foregoing specific illustration of my method is by way ofillustration and not of limitation. Itis my intention that the inventionbe limited only bythe a pended claims, or their equivalents, in whic Ihave. endeavored to cover broadly all inherent ndvelty.

I claim:

1. The method of reducing tar residuum produced by heating petroleumoil,- under pressure, ina confined stream to a cracking temperature,retaining the cracked material, under pressure, in' a digestion zone,continuously withdrawing cracked material from the digestion zone anddischarging it into a zone'maintained under reduced pressure to producea first vapor and 'a tar residuum, which comprises continuouslydischarging the tar residuum without substantial loss of heat into azone maintained under vacuum,

stripping the material in said zone maintained under vacuum to theextent necessary to produce aresiduum of commercial asphalt.

2. The method of reducing tar residuum produced by heating petroleumoil, under pressure, in a confined stream to a cracking temperatureretaining the cracked material, under pressure, in a digestionzone,-continuously withdrawing cracked material from the digestion zoneand discharging it into a zone maintained under, reduced pressure toroduce a first vapor and a tar residuum w ich comprises continuouslydischarging the tar residuum without substantial loss of heat into azone maintained under vacuum to produce a second vapor and a liquidresiduum,

- contacting the liquid residuum counter-cur-.

rently with steam to the extent necessar to produce a residuum ofcommercial as alt. 3. The method of reducing tar resi uum produced byheating petroleum oil, underpressure, in a confined stream to a crackintemperature, retaining the cracked materia under pressure, in adigestion zone, continuously withdrawing cracked material from thedigestion zone and dischar ing it into a zone maintained under reducec lpressure to produce a first vapor and a tar residuum which comprisescontinuously discharging the tar residuum without substantial loss ofheat into a zone maintained under vacuum to produce a second vapor and aliquid residuum, heatin the liquid residuumin said zone maintaine undervacuum and counter-currently contacting steam therewith to the extentnecessary to produce a residuum of'com-- inercial asphalt.

sure in a confined stream to a crackin tem-- gerature, retammg thecracked materlal un- 4. The method of making asphalt which comprisesheating petroleum oil under pressure in a confined stream to a crackingtemperature, retaining the cracked material under pressure in a di stionzone, continuously withdrawing crac ed material from the digesting zone,combining therewith petroleum oil containing tar-forming constituents,discharging the combined materials into a zone maintained under reducedpressure to pro-1 duce a first vapor and a tar residuum and continuouslywithdrawing the tar residuum without substantial loss of heat to stripthe sailmf to produce a residuum of commercial asa t. a

p 5. The method of making asphalt which comprisesheating petroleum oilunder preser pressure in a digestion zone, continuously withdrawingcracked material from the digestion zone, combining therewith petroleumoil containing tar-forming constituents, discharging the combinedmaterials into a zone maintained under reduced pressure to produce afirst vapor and a tar residuum, continuously withdrawing the tarresiduum and discharging the same without substantial loss of heat intoa zone maintained under vacuum, stripping the tar residuum in said zonemaintained under vacuum to the extent necessary to roduce a residuum ofcommercial asphalt. n testimony whereof, I have signed my name to thisspecification this 5th day of July, 1928.

PERCY O. KEITH, JR.

